More SplitPanes

Here is some code demonstrating some of the features of JTree,
DMTN (DefaultMutableTreeNode), and JSplitPane - this is not
perfect since the desired splitting doesn't seem to work until the
JFrame is resized. I am still working on fixing that problem.

// File: JTreeExample2
// Date: Jul 19, 2013
// Author: Nicholas Duchon
// Purpose: a quick demonstration of populating and presenting a
JTree
// createDataTree creates a tree structure directly
as a JTree using DefaultMutableTreeNode's as elements of the
tree
// the DMTN references Element's, which are really
any Object you wish to define.
// Display - this code shows how to display the
results of various traversals also.
// Also added JSplitPane's to present traversals in
GUI's
// Notes -
// DMTN only has one set of children at each node,
so if your project is more complex, you will need to fix this
somehow.